Electrical question

[Team4LongGun]

Thank you to all, especially those responding to my specific criteria. This is very helpful.

 

[Schmo]

@Team4LongGun,
Maybe this is all settled now, but I’ll chime in. In conduit is best and future-proof, but it’s not a requirement. With what you want to do, just get AL direct bury wire and send it. Looks like the electricians here have figured wire size and voltage drop.

If you need an equipment grounding conductor, meaning 4-wire cable instead of just 3-wire cable, your best option would be to go to an electrical supply house and get 2/0 MHF cable, also known as 2/0 mobile home feeder wire. It’s rated for direct burial.

 

[def90]

Conduit, and over size the wire for what you think you will ever need.

 

[Schmo]

Conduit, and over size the wire for what you think you will ever need.

When you only have a 50A supply, what would be the point in over sizing wire?

 

[def90]

When you only have a 50A supply, what would be the point in over sizing wire?

Because some day down the road you start spending more time in your shop and decide that you want something more than lights.

 

[Team4LongGun]

Because some day down the road you start spending more time in your shop and decide that you want something more than lights.

Great looking ahead, but I have addressed this several times, and it has been missed.

This is ONLY ever to be storage. I have a finished shop. This is a pole barn and only needs lights.
The good idea fairy is alive and well!

Several of you have helped me dial this in, thank you.

 

[Schmo]

Because some day down the road you start spending more time in your shop and decide that you want something more than lights.

I understand, but when he has been specific, multiple times, about only needing lights and some outlets, and only has a 50A supply, I’m just gonna tell him how to do that properly.

I’m not jumping on your case, just trying to help the OP.

 

[lil' bear]

Southwire 250 ft. 6/3 Gray Stranded CU UF-B W/G Wire 14782703 - The Home Depot

Visit the Home Depot to buy Southwire Company 250 ft. 6-3 UF Wire Gauge Service Entry Electrical Cable 14782703

www.homedepot.com

There's no need to overcomplicate the situation. I would use a conduit as risers coming in and out of the ground. But you can just leave the ends in the ground and direct bury the rest.
With that much distance expect some de-rating. I wouldn't try to push a full 50 amps. But otherwise that is plenty for just some lights and plugs.

 

[lil' bear]

Cat6 Direct Burial Ethernet Cable｜Shielded

Shielded Cat6 direct burial ethernet cable for outdoor use. 10Gbps speeds, 550MHz, pure solid copper, waterproof, UV resistant, 500ft/1000ft bulk reel.

www.truecable.com

If would recommend throwing one of these in that trench too while it's open. If you want internet out in the barn.

But after thinking about it. I would honestly put a 40 amp main breaker in your sub-panel just to be safe because of the distance. Even though it's being fed by a 50.

But for reference I put 40 amps in my garage and have a table sander, drill press, band saw, commercial freezer ect... you will still have plenty of juice.

 

[Team4LongGun]

Cat6 Direct Burial Ethernet Cable｜Shielded

Shielded Cat6 direct burial ethernet cable for outdoor use. 10Gbps speeds, 550MHz, pure solid copper, waterproof, UV resistant, 500ft/1000ft bulk reel.

www.truecable.com

If would recommend throwing one of these in that trench too while it's open. If you want internet out in the barn.

But after thinking about it. I would honestly put a 40 amp main breaker in your sub-panel just to be safe because of the distance. Even though it's being fed by a 50.

But for reference I put 40 amps in my garage and have a table sander, drill press, band saw, commercial freezer ect... you will still have plenty of juice.

I will do that ethernet cable, great idea.

Good to know your running those things on 40 amps, that is plenty for what we need.

 

[Mike D Texas]

Be careful listening to some of the “internet electricians”. Some have given spot on advice, some not so much.

Here is the answer to your wire size. This is for copper conductors. Aluminum will need a larger wire.


You will need (3) #4 and (1) #10 ground wire.

I personally would never direct bury wire even if it’s rated for such. It will fail sooner than later and you will be replacing it.

You can technically use a 1” sch40 PVC conduit but I would upsize to 1-1/4 or 1-1/2. You never know what your future needs may be.

Hope this helps answer your question.

What are you planning to do at the RV receptacle? If you have no plans to use it, I would just remove it and replace it with a nema 3R junction box and wire in direct.

 

[HuntHarder]

Everyone poo pooing on DB, how quickly do you think it fails? There are literally hundreds of thousands of houses that had DB wire services installed in the 60's-90's. To this day, many of them are still working. Many have faulted, but for this guy's needs and wants, it seems just fine. Extra care when installing it and good non rocky shading is key. Also, seems like minimal load will be applied to said wire in the OP's case. Obviously not the best way, but plenty functional and at a fraction of the price vs. conduit install.

 

[Stache Attack]

Direct bury wire is always an option. Since I’ve done both I would run pvc/ conduit. Very flexible for down the road. The upfront cost is not much more.

You state this is just storage, but you are going to run cat6 cable in? For resale I’d do it though I don’t know if that would ever be in your plans though.

 

[Mike D Texas]

Everyone poo pooing on DB, how quickly do you think it fails? There are literally hundreds of thousands of houses that had DB wire services installed in the 60's-90's. To this day, many of them are still working. Many have faulted, but for this guy's needs and wants, it seems just fine. Extra care when installing it and good non rocky shading is key. Also, seems like minimal load will be applied to said wire in the OP's case. Obviously not the best way, but plenty functional and at a fraction of the price vs. conduit install.

When I worked a service van one of the most common calls we fielded was tripped breakers that wouldn’t reset. Probably 80% of the time it was direct bury cable that had failed. Most of the time it was insulation breakdown causing a direct fault, sometimes it would be wet soil causing faults. Sometimes it would be rocks or something else that compromised the insulation. I’ve seen failures as soon as 5 years after installation and I’ve seen some that lasted 25 years.

Everyone has to weigh their options.

 

[Mighty Mouse]

If you truly want the minimum to achieve the use case you described (lighting + light duty receptacles), put a 15A or 20A breaker where you’re tying into the existing circuitry and size your new conductor to the barn accordingly. You could add the new small breaker downstream of the existing 50A RV receptacle or downsize that 50A breaker back at the panel if you no longer need the RV receptacle. A 15A circuit would be fine for lighting and small tools/appliances; 20A would be better for handling the starting current of a table saw and compressor.

As a lower cost option, I would strongly consider 12VDC lighting powered by a battery bank and solar panel and a 2000W inverter generator to run tools when you need them.